Ch. 12.10 Neurotransmitters and Neuromodulation

Question 1

What are the four classifications of neurotransmitters?

Answer 1

Acetylcholine
Biogenic amines
Amino acids
Neuropeptides

Question 2

Acetylcholine

Answer 2

Very different than other neurotransmitters

Question 3

Biogenic amines

Answer 3

Derived from certain amino acids by the removal of a carboxyl group and the addition of another function group by enzymatic pathways in the cytosol.
Function group added determines if the Amines belong to the catecholamines or indolamines

Question 4

Catecholamine examples

Answer 4

Dopamine, epinephrine, or nor-epinephrine

Question 5

Indolamine examples

Answer 5

histamines (synthesized from histidine) or serotonin (synthesized from tryptophan)

Question 6

Amino acids

Answer 6

Glutamate, aspartate, serine, glycine, gama aminobutyric acid (GABA).

Question 7

Neuropeptides

Answer 7

Chains of amino acids that range in length from 2-40 acids.

I.E. Opiates, enkephalins, beta-endorphines, and substance P.

Question 8

Direct neurotransmitters

Answer 8

Bind directly to the receptor sites

Question 9

Indirect neurotransmitters

Answer 9

Neurotransmitter bind to a receptor that activates the second messenger pathway involving G-protein.
Can trigger much more diverse effects like the opening of ion channels, activation of existing enzymatic pathways, and transcriptions of genes for the synthesis of new proteins.

Question 10

What are the main attributes of ACh?

Answer 10

Synthesis
Removal from the synaptic cleft
Interaction with target cells

Question 11

What is ACh synthesized from?

Answer 11

Acetate and choline

Question 12

What happens when acetylcholine is digested by acetylcholinesterase?

Answer 12

Broke down into acetate and choline and the choline is taken up into the neuron that released the ACh.

Question 13

What are other means of removing neurotransmitters from the synaptic cleft?

Answer 13

1) Re-uptake of the transmitter into the synaptic knob and enzymatic digestion of the neurotransmitter.
2) Diffusion from the synaptic cleft and re-uptake by surrounding glial cells.

Question 14

What are the types of receptors that ACh binds to?

Answer 14

Nicotinic- direct interaction

Muscarinic- use second messenger passageway involving G-protein.

Question 15

Define neuromodulation

Answer 15

The release of chemical (other than the classic neurotransmitters) from cells that locally regulate or alter the response of neurons to neurotransmitters.

Question 16

Facilitation

Answer 16

Greater response from a postsynaptic neuron because of the release of neurotransmitters.

Question 17

Inhibition

Answer 17

Less response from a postsynaptic neuron because of the release of neuromodulators.

Question 18

Enkaphalines

Answer 18

A neuromodulator that blocks the sense of pain by blowing the transmission of the sensory input at the level of the spinal cord.

Question 19

Why is Nitrix oxide different than normal neurotransmitters?

Answer 19

Short live gas synthesized from arganine on an as needed basis
Non-polar, produced and released from post-ganglion neurons
enters presynaptic neurons forming retrograde communication
Functions in the brain to help develop memories by causing the increased release of neurotransmitters
Causes smooth muscle relaxation blood vessels

Question 20

Endocannibinoids

Answer 20

Binds with the same receptors as THC
Decreases neurotransmitter release from presynaptic neurons. This alters learning and memory, affects appetite, and surpasses nausea.